Intermittent feed measuring mechanism



Se t. 21, 1965 R. A. HALBERG 3,207,400

INTERMITTENT FEED MEASURING MECHANISM Original Filed April 27. 1961INVENTOR. 055,004 #44 550 B United States Patent 1 Claim. (Cl. 226136)This invention relates to a variable feed measuring mechanism for sheetmaterial, such as photosensitive paper or film. This application is adivision of U.S. Serial No. 106,039, filed April 27, 1961, now PatentNo. 3,181,416.

For many years the darkroom enlarger has been conventional equipment inboth the commercial and home photographic laboratory. Recently equipmenthas been developed which permits both viewing and printing of a visibleimage in varying degrees of enlargement. In order to minimize waste ofthe photosensitive film or paper it is desirable to control the amountof film or paper being fed into the development section of the equipmentin accordance with the amount of film or paper exposed to the lightimage. Reliability and simplicity of operation are obviously importantfactors in a device to accomplish these purposes.

It is an object of this invention to provide a variable feed measuringdevice to minimize waste of film or paper.

For purposes of convenience and clarity, the description of the deviceof this invention will refer to the figure.

The figure is a side view of the film or paper measuring device, partlybroken away to show detail and partly in schematic.

In the paper or sheet measuring device of the figure, developer drivemotor 77 contains a pop-out rotor connected to a shaft which engages thereduction gears in gear box 82 only when the motor is energized. Powerdrive shafts 83 and 83' transmit the power output of the reduction gearbox 82 to gear 84 and to developer roll drive gear 86 on shaft 83through single acting clutch 85. Gear 86 drives the paper or sheet feedroll and, because of single acting clutch 85, is capable of rotation inonly one direction. Spring 91 connects to shaft 83 and is so disposed asto oppose the motor driven direction of rotation of shaft 83. Gear 84 ispermanently coupled to measuring gear 87 and transmits power tomeasuring gear 87. Measuring gear 87, which has a stud or boss 88 on theperipheral edge of its outer face, is rotatably mounted at the free endof axle 92, the other end of which is affixed to the frame or a suitablefixed member. Arm 90 is attached to measuring gear 87 and, when no poweris supplied to the motor, is maintained, by the tension of spring 91, incontact with stop 89 extending outwardly from the frame. Opposite theouter face of measuring gear 87 and aligned with the axis thereof ishollow shaft 93 on which is rotably mounted gear 97. To gear 97 isaffixed U-shaped spring arm 96, the free end of which is in closeparallel relationship to the outer face of measuring gear 87. Slidingpin 94 is positioned in hollow shaft 93 and extends slightly from theopen end thereof. The other end of pin 94 is connected to spring switch95, which it activates when depressed. Spring switch 95 is located inthe circuit supplying electrical power to motor 77. Gear 97 andtherefore spring arm 3,207,400 Patented Sept. 21, 1965 ice 96 can berotated from an external knob or control through a flexible cable 99 andintermediate gear 98.

In operation on a variable enlarger and printer for image reproduction,this paper feed device is generally used in conjunction with a variablemast, since the positioning of such a mask can be made to effectivelyregulate the length of photosensitive paper that will be struck by theprojected image. The paper feed device can be integrally connected withthe mask to automatically feed the proper length of photosensitive paperfor a particular mask setting, or the viewing screeen of anenlarger-viewer apparatus can be suitably calibrated and the paperdevice can be separately operated and controlled in accordance with theappropriate scale reading appearing on the viewing screen. The externalcontrol of flexible cable 99 permits rotation of gear 97 and positioningof the free end of spring arm 96 to any desired points adjacent theouter face of measuring gear 87 at the periphery thereof. In a daylightenlarger as described in U.S. Serial No. 106,039, filed April 27, 1961,exposure of the photosensitive copypaper the developing sequence isinitiated, the motor 77 is activated, and the pop-out rotor engages gearchain 82 and drives gear 86 through clutch 85, thus rotating the feedroll to advance the paper or film. The rotation of shaft 83 alsoovercomes the opposition of spring 91, increasing the tension in saidspring, and drives measuring gear 87, which rotates until stud 88contacts the free end of flexible spring 96. This forces spring 96 awayfrom the outer face of gear 87, thereby depressing pin 94 and actuatingswitch 95 to shut off power to the motor 77. With the motor deenergized,the pop-out rotor disengages from the gear chain 82, permitting thetension in spring 91 to reverse the direction of rotation of measuringgear 87 until arm once again contacts stop 89, the original startingposition. During the reverse rotation of measuring gear 87, no power istransmitted to gear 86 because of the slippage of single-acting clutch85. The paper feed device thus resets itself for another developingcycle.

Although in the embodiment illustrated only the essential parts areshown and described in detail in order to facilitate comprehension ofthe principles involved, it will be understood that modifications canreadily be made without departing from the scope of the invention.

I claim:

A variable feed device for paper, film and the like which comprises afeed roll, a supported rotatable drive shaft, a power source for saiddrive shaft, disengageable coupling means between said power source andsaid drive shaft which is engageable only when said power source isactivated, means for biasing said drive shaft counter to the directionof rotation provided by said power source, stop means to limit counterrotation of said drive shaft, a single acting clutch operated by saiddrive shaft, a power transmission shaft connected to the output of saidclutch, means for connecting said power transmission shaft to said feedroll, said clutch being only capable of trans mitt-ing unidirectionalrotation to said power transmission shaft when said power source isactivated, a measuring gear permanently coupled to said drive shaft andbeing rotatably mounted on a supported shaft, a non-axially disposedboss on one face of said measuring gear, an electrical switch foractivating said power source, said switch having an actuating member inclose axial relationship to the aforesaid face of said measuring gear, aspring arm adjustably located between said activating 3 4 member and theaforesaid face and in such relationship to References Cited by theExaminer said measuring gear face as to contact said boss upon ro-UNITED STATES PATENTS tation of said measuring gear, thereby to tripsaid switch actuating member and operate said switch, and means for2,737,278 3/56 Batten 192142 X adjusting the position of said spring armto provide such 5 2,984,012 5/61 Grou 226*134 X contact after apredetermined rotation of said measuring gear, thus to provide apredetermined rotation of said HENSON WOOD Primary Exammer' powertransmission shaft. ROBERT B. REEVES, Examiner.

